Kathmandu to Lhasa

1. Most people stop at Everest Base Camp, Sakya monastery, Shigatse, Gyantse and Yamdrok Lake on their way to Lhasa.
   
   2. Most people take 5 to 7 days.
   
   3. In the winter months you can drive all the way up. Otherwise you have to hike or take other means (cart, horse)
   
   4. I can't remember how far in 4WD's can go. I always go to Everest in the winter when the Himalaya see blue skies most days.
   
   5. 5200m
   
   6. There are many to choose from in Kathmandu. Take your time and price out several places before making a final decision. I would use the Trekkers Society, but they are only one of many agencies that can arrange travel for you.
   
   7. Not cheap coming from the Nepal side. Most prices for this type of trip are between $400 and $550 per person. I do it starting from Lhasa and it only costs around $125 per person (in low season).

I did it two years ago. Great experience , esp. since all of us had acclimatised well to 3000+ beforehand. I´ve seen people faring a lot worse on Himalayan roads , so this would be my first advice : get some time at high altitude before starting out.

Our group got delayed and stayed overnight in Zhangmu , 2300 meters, just across the border. It´s either there . or more frequently , Nyalam at 3775 , then the next day to Lhatse around 4000 going over a 5000 meter pass. Sleeping at/near 4000 meter within two days can definitely mean problems , I suggest you read up on AMS at highaltitudemedicine.com.